(Radio Iowa) – The attorney for one of the Fairfield teenagers accused of murdering high school Spanish teacher Nohema Graber is challenging evidence gathered in the investigation. Willard Chaiden Miller and Jeremy Goodale were both 16 years old when Graber was killed on November 2nd of last year. Miller’s defense attorney says police gave Miller’s mother false information to convince her to sign a permission form approving an interrogation.

That’s Annalisa Clifford Gold, the mother of one of the suspects. She spoke a court hearing Wednesday with her son’s attorney, Nathan Olson. Clifford Gold testified that once she reached the police station where her son was being interviewed, she asked repeatedly to see him, but was not allowed in the room. Prosecutor Scott Brown, an assistant attorney general, said the 16-year-old — who is being tried in adult court — told investigators he understood his rights to stay silent and ask for an attorney before the interview started. And Brown said permission forms meant to protect juveniles do not apply in cases like this.

Brown said in Iowa, teens who are 16 or older and accused of serious crimes like murder are not protected by juvenile court rules. The judge who presided over the evidence hearing did not indicate when he might rule on the objections. Miller is set to stand trial in March in Council Bluffs. Court documents released this week suggest a possible motive for Graber’s murder. Miller allegedly met with the Spanish teacher on the day of her murder, to discuss his grades.